Geokge ii



eE'oneE n. enosnv, or Elis'r s'oMEnviLLE, MASSACHUSETTS.

"-l-MFR OVVLEMENTIN SAETYrl] ALVES.

` Specification forming part of Letters l?a.tent No.4 .lidh, dated May 5,'174; applicationlled March l20,1e74. Y

To all whom t may concern:

le it known that L'GEQRGE Il. CROSBY, of East Somerville, Middlesex county, M assaehu-` setts, have invented certain new and useful. Improvements in SafetyValves, of which the following is a specification:

M y invention consists in a corrugated face or hearing for a-satety-valve, and the correspondin g corrugated seat for the same, the wliole so arranged that the face and seat shall match and make one continuous hearing capa' hle ot' being ground together', and hrming a tight joint. v

lhe objects I have in view are,first, to have tlievalve open the desired maximum pressure, and to remain .open untnthe pressure has heen reduced to the minimum desired, and then to close; second, to have the; valve to open at the desired maximum pressure, and to he so operated that should steam be genen' ated ever so fast the valve will open wide 'enough to relieve the boiler of all pressurein excess of the maximum desired.

These results are accomplishedflrst, by having the outside dia-meter of the hearing considerably in execssvo'f the inside diameter, and the hearing corrugated, thus giving-a larger arca for the steam to act on after the valve is open` than when it was closed, and consequently tending to raise the valve higher; second, when the valve' is open the zigzag or crooked, passage through which the steam has to escape compels" the steam to constantly change its motion, impinging at every angle or turn, and consequentlycreating a lifting power 1n addition` to the direct pressure o'' steam in the boiler 5 third, the steam in its es-v cape through this crooked opening orsinuous path when the valve is raised forms a vcushion or impediment to beovercome before the valve can close.

The nature of my invention, and the manner in which the .same is or may be carried into effect, will he readily understood by reference to ,the accompanying drawing, in which i I. Figure 1 is a perspective view of a safetyv valve made in accordance with my invention. Fig. 2 is a longitudinal vertical central section of the same; 1 v

The safetyvalveshown Vin illustration of' my invention is, i'nits general organization, one of the old andwell-known forms ot' safety-valve. 'To the hed A of the valve-seat are axed the upright guide-rods l, screwthrezuled, as shown. lOn them tits loosely the presser-har C, which, at its center, is perforated for the passage of the valvestem D. The har rests on the Iupper hearing vblock or ring of the spring E, which, at vits lower end, has another corresponding bearingring resting -on the valve. The rods B are provided with nuts F, hy which the pressure ofthe har on the spring;l is regulated; These parts are all of the usual construction, and operate together inthe or- I have represented the valve-seat with. auV v outside smaller rib, a, but this 1s supertluous,

and'can be dispensed with. The effect of this formation oi' the valve and itsseat has been above stated, and requires 'no repetition here. The object 1s to give the steam a crooked, zigzag, or sinuous passage, and to this end the corrugations may be `formed in various ways, as, for instance, instead ot' vbeing V-shaped, they may ber round-nosed,7

square, or ot' other suitableshape.v y 'The valve and valve-seat, under anyand all conditions, must, ot' course, Abe soiormed that when the valve is down itwill lit the valveseat closely.

Other modifications might he suggested, but the above are suiiieient to indicate the variety.

ot' ways in which the invention may nevar-- ried into effect. But undetiall circumstances the corrugations must'be olf such depth that, no matter to what extent the valve maybe lifted under the ordinary conditions of use, the oppositely-placed ribs of the valve and valve- Aseat shall still intercept each 'other in'vsueh manner as to'presentlto the steam a series ot' deectin g-surfaces, which will force thesteam to travel iny a zigzag or sinuous pathto eteet itsescape.v

l, The* invention is,` of'4 course, applicahleto other stylcs of safety-valve, whether'sprng o1' weighted. 1 l 'v Having now doscribcdjny invention, and the manner in which the same is to be; carried into effect, whatl claim, and desire to' secure by Lott-ors' latent, is r `In n safety-'valve7 the combination of -aribbed volvo-sont and n ribbed valve proper, tho same being constructed as herein shown and set' fo1tl1,"'so that under any conditions of use the ribs of the val'io will intercept the ribs of the valve-sent, in such manner :is to 'orco the escaping steam to travel in n sinnous o1' zigzag path, for the purpose specified.

Intestimonywhereof I have hereunto signed my mime this 18th davy of March, 1874.

f GEO. H. CROSBY. Witnesses JOHN MAY, AUGUSTUS SoHULz. 

